I prefer Blood-Spray Bite in a vacuum, but really it depends on what else you're doing with the character, and what your portion of the party's tactics will entail. BSB helps you group enemies for AoE's (yours or someone else's), force enemies over to your defender and away from any squishy types, and is useful if someone in your party relies on positioning for extra benefits. Latch On is nice single target control against artillery, some lurkers and controllers, and the occasional skirmisher, but weak against soldiers, brutes, and enemies who are fine with standing still in melee combat.
t~